In the field of fastening or securing component parts, there are numerous applications in areas wherein it is impossible to fasten the parts by reason of not having sufficient working space for the fastening devices or for the required tools. There have been various ways and means for connecting parts in confined spaces, for example, the use of compression tools, high-strength adhesives, upsetting connectors and the like. There has been the requirement, in addition to the securing or fastening of two or more metal pieces or parts, that two plastic parts or a plastic and a metal part need to be secured together. With the advent of the use of plastics for the framework or the enclosures for various machines, it is still essential that certain metal components be utilized for some parts of the machines. It is also known in the art that bonding or welding of metal to plastic is entirely feasible, and that such method of securing these dissimilar materials is common practice.
Representative prior art in method and apparatus for bonding of plastic materials in U.S. Pat. No. 3,022,814, issued to A. G. Bodine on Feb. 27, 1962, which discloses sonic bonding of two thermoplastic materials, a thermoplastic material and a metal body, or two metal bodies by using the thermoplastic material as the bonding agent.
U.S. Pat. No. 3,184,353, issued to L. Balamuth et al. on May 18, 1965, discloses the fastening together of members by high-frequency vibrations, such members being two plastic members or a plastic member and a metal member.
U.S. Pat. No. 3,278,211, issued to G. Baas et al. on Oct. 11, 1966, shows a metal-to-nonmetal seal wherein the nonmetallic material fills the spaces in the metal member around a lead-in conductor.
And, U.S. Pat. No. 3,483,611, issued to L. Balamuth et al. on Dec. 16, 1969, discloses methods and apparatus for assembling parts together by ultrasonic energy, the parts being metal and metal, plastic and plastic, or metal and plastic.